CN1295843C

CN1295843C - Oil dynamic pressure bearing motor, oil dynamic bearing device and its mfg. method

Info

Publication number: CN1295843C
Application number: CNB031311830A
Authority: CN
Inventors: 五明正人; 芦部升; 杉信进吾
Original assignee: Nidec Sankyo Corp
Current assignee: Nidec Corp
Priority date: 2002-05-17
Filing date: 2003-05-16
Publication date: 2007-01-17
Anticipated expiration: 2023-05-16
Also published as: CN1463066A; US20040013331A1; US7059771B2

Abstract

A oil dynamic pressure bearing motor is provided with the rotation member 20 fitted onto a peripheral surface of the rotation shaft 16 and integrally rotated/driven with the rotation shaft 16; a diameter enlarged part 28 formed on the dynamic bearing member 14; the dropping off prevention member 30 provided on the rotation member 20 and preventing dropping off of the rotation shaft 16 by axially overlapping with the diameter enlarged part 28 of the dynamic pressure bearing member 14; and a seal part 32 axially extending from the outside of an axial opposed surface of the dropping off prevention member and the diameter enlarged part 28 and inhibiting flowing out of a lubrication oil 18 to the outside. An axial recessed part 38 is formed on an opposed part of the rotation member 20 to at least the diameter enlarged part 28 and the diameter enlarged part 28 is arranged in the recessed part 38. The joint part 36 of the rotation member 20 and the rotation shaft 16 and the diameter enlarged part 28 are radially overlapped. The invention capable of sufficiently ensuring joint length of a rotation shaft and a rotation member, thickness of a dropping off prevention member, length of a capillary tube seal part and length of a joint part of a dynamic pressure bearing member and a base plate.

Description

Oil dynamic bearing electric motor, oil dynamic bearing arrangement and manufacture method thereof

Technical field

The present invention relates to have rotating shaft and hydrodynamic bearing member and rotating shaft and hydrodynamic bearing member can be mutually with the counterrotating oil dynamic bearing electric motor of contactless state, oil dynamic bearing arrangement and manufacture method thereof, for example, can can also be used as the drive motor of the various devices that require high running accuracy in addition as the disc drive motor of disk, CD etc.

Background technology

As the drive motor of the various devices that require high running accuracy, use the oil dynamic bearing electric motor that adopts the oil dynamic bearing arrangement.For example, in hard disk drive, the packing density of hard disk is increased, corresponding therewith, it is more and more higher that the rotary speed of disc and running accuracy also become.According to the requirement of the high rotation speedization and the high running accuracyization of disc, the suitable oil dynamic bearing electric motor that adopts the oil dynamic bearing arrangement that uses.

For the high rotation speedization and the high running accuracyization of seeking the oil dynamic bearing electric motor, the bonding length that the engagement member that extends is mutual, in addition, in order to improve the rigidity of hydrodynamic bearing, guaranteeing to make the bearing scope of utilizing the radial dynamic pressure bearing is effective at axial growth.On the other hand, in order to keep more longways the life-span of dynamic pressure motor, hope can worked hard aspect the lubricating oil that enclose q.s, in addition, preferably has abundant space and can dispose and be used to the sealing device that prevents that lubricating oil from spilling.

About with the corresponding oil dynamic bearing arrangement of above-mentioned requirements, the applicant applied for patent in the past.It is exactly this example that the Japan Patent spy opens the invention that the 2001-65552 communique recorded and narrated.The example of quoting with the oil dynamic bearing electric motor of the constructed in fact thought of the described invention of this communique is shown in Figure 11, Figure 12.Below, Figure 11, oil dynamic bearing electric motor shown in Figure 12 are described.In addition, in Figure 11, Figure 12, partly be that the center is described with hydrodynamic bearing, motor portion is omitted.

In Figure 11, symbol 16 expression rotating shafts, symbol 14 expression hydrodynamic bearing members.Hydrodynamic bearing member 14 is roughly drum, leaves minim gap ground therein in the heart hole and embeds rotating shaft 16.On rotating shaft 16, engaged rotating member 20 in methods such as the part utilization outstanding from the upper end of hydrodynamic bearing member 14 are pressed into.In this embodiment, rotating member 20 is the wheel hubs that put disc and rotate.The full week at the junction surface of rotating shaft 16 and rotating member 20 is soldered or utilize containment member to seal, so that the lubricating oil 18 that the generation dynamic pressure is used does not spill to the outside.

Above-mentioned hydrodynamic bearing member 14 has: form the wide diameter portion 28 that the cylindrical portion of radial dynamic pressure bearing 26,26 usefulness, the axial hydrodynamic bearing 34 that is formed on this cylindrical portion outer circumferential side form usefulness.This wide diameter portion 28 upward forms flange shape in an end of above-mentioned cylindrical portion (being the left part among the figure).Be formed with radial dynamic pressure at the above-mentioned cylindrical portion inner peripheral surface of hydrodynamic bearing member 14 groove takes place to use, be formed with the axial hydrodynamic groove at the end face of above-mentioned wide diameter portion 28 sides.Groove takes place use in above-mentioned radial dynamic pressure, at 2 places up and down of the cylindrical portion inner peripheral surface of hydrodynamic bearing member 14 along complete all and form.Above-mentioned axial hydrodynamic takes place also to form along full week of the end face of wide diameter portion 28 sides with groove.

In the cylindrical portion of above-mentioned hydrodynamic bearing member 14, be pressed into all-in-one-piece rotating shaft 16 with rotating member 20 from the upside insertion.Prevent member 30 from the coming off of ring-type of periphery downside insertion of hydrodynamic bearing member 14, and engage with the inner peripheral surface 54 of rotating member 20.Rotating member 20 has the smooth stage portion 56 continuous with above-mentioned inner peripheral surface 54, and this stage portion 56 also prevents that with above-mentioned coming off member 30 from engaging.In addition, spill in order not make lubricating oil 18 described later, end with envelopes such as bonding agents at the junction surface that prevents member 30 and rotating member 20 that comes off.In the lower end of hydrodynamic bearing member 14, be formed with as described later along all grooves 100 (referring to Figure 13) of the concentric circles in full week, in this groove 100, embeds the cover 22 of flat block shape, with covering 22 lower ending openings of sealing hydrodynamic bearing member 14 in week.Cover 22 ends with envelope such as bonding agent 24 grades in all grooves in the lower end of above-mentioned hydrodynamic bearing member 14.

Between the outer peripheral face of the inner peripheral surface that prevents member 30 and the hydrodynamic bearing member 14 relative that comes off with it, prevent above the member 30 and between below the wide diameter portion 28 of the hydrodynamic bearing member 14 relative coming off with it, between the peripheral wall surfaces of the outer peripheral face of above-mentioned wide diameter portion 28 and the rotating member 20 relative with it, between on the end face of rotating member 20 and the above-mentioned wide diameter portion 28 relative with it, between the outer peripheral face of the inner peripheral surface of hydrodynamic bearing member 14 and rotating shaft 16, and be formed with the gap between the lower surface of above-mentioned cover 22 and rotating shaft 16.These gaps are pressed said sequence mutually and are communicated with, and are filled with lubricating oil 18 in this gap.The gap that comes off between the outer peripheral face of the inner peripheral surface that prevents member 30 and the above-mentioned hydrodynamic bearing member 14 relative with it is open downwards.In addition, above-mentioned hydrodynamic bearing member 14 comes off relatively and prevents the outer peripheral face of member 30 inner peripheral surfaces, become the conus portion that diminishes under the outer radial, gap between the outer peripheral face of above-mentioned the come off inner peripheral surface that prevents member 30 and hydrodynamic bearing member 14 becomes the capillary seal portion 32 that it enlarges at interval gradually downwards.The liquid level of lubricating oil 18 is arranged in this capillary seal portion 32.

Lubricating oil 18 is injected into above-mentioned gap from above-mentioned capillary seal portion 32.Be formed with axial hydrodynamic bearing 34 between the end face of the end face of wide diameter portion side above-mentioned rotating member 20, above-mentioned and above-mentioned wide diameter portion 28 sides relative with it, two places up and down between the outer peripheral face of the inner peripheral surface of hydrodynamic bearing member 14 and rotating shaft 16 are formed with radial dynamic pressure bearing 26,26.In these hydrodynamic bearings, accompany above-mentioned lubricating oil 18.

In the downside of hydrodynamic bearing member 14 periphery of half approximately, the chimeric interior all sides that are fixed on the cylindrical portion that is formed at base plate 10 central parts shown in the with dashed lines.Base plate 10 enters in rotating member 20 near coming off in above-mentioned cylindrical portion and prevents member 30.Symbol L represents the axial bonding length of base plate 10 and hydrodynamic bearing member 14 among Figure 11.

Be formed with columnar perisporium 44 in the lower end of rotating member 20, not shown drive magnet is installed on the outer peripheral face of this perisporium 44.Constitute the rotor of motor by this drive magnet, rotating member 20, rotating shaft 16.On the other hand, on base plate 10, fixing by not shown iron core, be wound on the stator with a plurality of prominent motor of extremely going up that drive coil constituted of this iron core one.The prominent utmost point of this stator leaves appropriate gap with the outer peripheral face of above-mentioned drive magnet and relative, thereby drives rotor by the energising rotation of switching to drive coil.

Example shown in Figure 12 is the structure roughly the same with example shown in Figure 11, and the length of the thickness that prevents member 30 of coming off, capillary seal portion 32, hydrodynamic bearing member 14 are inequality with the length L at the junction surface of base plate 10.In the example of Figure 11, though fully obtained bonding length, the come off thickness that prevents member 30, the length of capillary seal portion 32 of rotating shaft 16 with rotating member 20, hydrodynamic bearing member 14 is insufficient with the length L at the junction surface of base plate 10.In example shown in Figure 12, fully obtain the bonding length, hydrodynamic bearing member 14 of rotating shaft 16 and rotating member 20 and the length L at the junction surface of base plate 10, but the length of the thickness that prevents member 30 of coming off, capillary seal portion 32 is insufficient the recoverable amount of lubricating oil is reduced, might make the lost of life of motor because of the evaporation of lubricating oil.In addition, base plate 10 is also insufficient with the bond strength of hydrodynamic bearing member 14.

In addition, used oil dynamic bearing arrangement has rotating shaft and hydrodynamic bearing member in above-mentioned oil dynamic bearing electric motor, accompanies lubricating oil in the minim gap between rotating shaft and hydrodynamic bearing member.Be rotated by the relative hydrodynamic bearing member of rotating shaft, formed dynamic pressure takes place to produce dynamic pressure with groove at least one side of rotating shaft and hydrodynamic bearing member thereby utilize, and utilizes this dynamic pressure that the relative hydrodynamic bearing member of rotating shaft is rotated with noncontact.About patent applied for before such oil dynamic bearing arrangement the applicant.It is exactly this example that above-mentioned spy opens the invention of being recorded and narrated in 2001-65552 communique and special hope 2001-349402 specification and the accompanying drawing.

The example of oil dynamic bearing arrangement used in the oil dynamic bearing electric motor shown in Figure 11 is shown in Figure 13.In Figure 13, on the hydrodynamic bearing member 14 of general cylindrical shape shape, on the axial both ends of rotating shaft patchhole face, the radial dynamic pressure that is formed with the major part that constitutes the radial dynamic pressure bearing takes place with groove 74,74.Insert in the hole at the rotating shaft of hydrodynamic bearing member 14 not shown rotating shaft is left between the face that inserts described rotating shaft patchhole in minim gap ground.Among Figure 13, on the upper surface of hydrodynamic bearing member 14, the jetty 102 of residual circle on periphery and form all grooves 100.Cover 22 embeds in this groove 100 in week.Cover 22 be flat cup-shaped, has the perisporium 221 of drum and has continuous with this perisporium 221 and to the vertical flange part that stretches out 222 of foreign side.This flange part 222 with the bottom surface state of contact of above-mentioned all grooves 100 under bonding agent 24 is filled in all grooves 100, to cover 22 by sclerosis and be fixed on the hydrodynamic bearing member 14, an end face of the hydrodynamic bearing member 14 of rotating shaft patchhole opening seals with cover 22.

As shown in figure 11, hydrodynamic bearing member 14 spins upside down from posture shown in Figure 13.The internal diameter of cover 22 perisporium 221 becomes identically with the internal diameter of hydrodynamic bearing member 14, and under the state of the rotating shaft patchhole that rotating shaft is inserted hydrodynamic bearing member 14, the end of rotating shaft enters in the cover 22.And, between the outer peripheral face of cover 22 perisporium 221 inner peripheral surfaces and rotating shaft 16, produce minim gap.In addition, the rotary body that comprises rotating shaft 16 is owing to utilize axial hydrodynamic bearing 34 to be supported in axially, also produces minim gap between the inner bottom surface of end face of rotating shaft 16 and the cover 22 relative with it.Accompany lubricating oil in these gaps, be rotated by the relative hydrodynamic bearing member 14 of rotating shaft, in radial dynamic pressure takes place with

groove

74,74 dynamic pressure takes place, rotating shaft is supported on the hydrodynamic bearing member 14 with contactless state.

In addition, quote with above-mentioned and special be willing to that the example of the oil dynamic bearing arrangement of 2001-349402 specification and the constructed in fact thought of the described invention of accompanying drawing is shown in Figure 14.In Figure 14, on an end face of hydrodynamic bearing member 14, around the peristome of rotating shaft patchhole, be formed with at circumferencial direction continuously and to all grooves 76 of the groove shape of axial depression.Be inserted with the cylindric perisporium 221 of the cover 22 of flat cup-shaped in this groove 76, an end face of the hydrodynamic bearing member 14 of rotating shaft patchhole opening seals with cover 22 in week.The outer peripheral face of cover 22 above-mentioned perisporium 221 contacts with the outside diameter peripheral wall surfaces of above-mentioned all grooves 76, and filling bonding agent and hardening on this contact-making surface seals and ends into the state that lubricating oil does not spill.

In recent years, general more and more higher, also more and more higher to the requirement of the slimming of oil dynamic bearing electric motor thereupon at hard disk drive and other requirement of installing middle-size and small-sizeization, slimming.For example, the what is called that hard disk drive has realized being called the card correspondence is the structure of type as thin as a wafer, and the height of its employed motor also is required to be limited in about 3mm.To realize to produce following variety of issue with Figure 11, structure shown in Figure 12 to the oil dynamic bearing electric motor that such height dimension extremely is restricted.

When rotating member 20 is engaged with rotating shaft 16, if both sides' perpendicularity low precision, the runout of the rotating member 20 when then rotating is just big, occasion at the disc drive motor, owing to disc carries the face runout disc is rotated with fluctuating, or because the vibration of disc and the air turbulence that produces because of the rotation of disc produces " magnetic head " not from the problem of disc come-up ormal weight, the problem that also exists the fault rate when making record regenerating to increase because of course deviation.In addition, because the back side of rotating member 20 is made the axial axis bearing surface, so if the perpendicularity of rotating member 20 relative rotation axis 16 is when worsening, the come-up rotating speed promptly uprises for the rotating speed of the axial buoyancy that obtains to stipulate, the time of rotating shaft 20 relative hydrodynamic bearing member 14 contacts is elongated, makes the problem of the reliability reduction of bearing so exist the increase of bearing wear amount.

In addition, in order to ensure the perpendicularity of rotating member 20 with rotating shaft 16, mutual bonding length must be more than the ormal weight.

Then, consider hydrodynamic bearing member 14 height, be axial length.The peripheral part of hydrodynamic bearing member 14 must have the gauge, the length with the corresponding length that prevents member 30 of coming off, capillary seal portion 32, base plate 10 of wide diameter portion 28 and the bonding length of hydrodynamic bearing member 14.In addition, the bonding length of base plate 10 and hydrodynamic bearing member 14 also must have not make the bond strength that moves or separate each other when applying impulsive force and vibration from the outside.Usually, engage with hydrodynamic bearing member 14, must fully guarantee bonding area in order to make base plate 10 with bonding agent.

As Figure 11, example shown in Figure 12, at the end position of axial hydrodynamic bearing 34 and radial dynamic pressure bearing 26 in the structure that axially is arranged in roughly the same position, when more and more being strict with the slimming of motor as in recent years, the situation that can not meet the demands can take place in the such structure of Figure 11, Figure 12 example.That is, as shown in figure 11, when obtaining rotating shaft 16 bonding length fully, during the length of the thickness that prevents member 30 of coming off, capillary seal portion 32, can not fully guaranteeing the length L at hydrodynamic bearing member 14 and the junction surface of base plate 10 with rotating member 20.As the example of Figure 12, when fully obtaining the length L at rotating shaft 16 bonding length, hydrodynamic bearing member 14 and the junction surface of base plate 10 with rotating member 20, can not fully guarantee the to come off thickness that prevents member 30, the length of capillary seal portion 32.

In addition, in the oil dynamic bearing arrangement, spy shown in Figure 13 opens the described invention of 2001-65552 communique, the cover 22 that envelope stop last item holds an end face of member 14 is flat cup-shaped, this cover 22 is fixed in all grooves 100 that are formed on hydrodynamic bearing member 14 1 end faces by bonding, and a part that becomes rotating shaft is inserted in the structure in the above-mentioned cover 22.Therefore, the axial effective length of hydrodynamic bearing member 14 is by the restriction of the part of above-mentioned all grooves 100, and radial dynamic pressure bearing up and down shortens at interval, exists the problem that becomes the low oil dynamic bearing arrangement of rigidity easily.In addition, on the contrary, desire to make radial dynamic pressure bearing up and down to increase, guarantee the rigidity of oil dynamic bearing arrangement at interval, then hydrodynamic bearing member 14 is elongated, and can not realize the slimming of oil dynamic bearing electric motor.Opposite with it, have and can fully guarantee hydrodynamic bearing member 14 and advantages base plate 10 bonding lengths.Becoming bonding agent 24 again invades in the bearings easily, promptly invades the structure in the rotating shaft patchhole.

On the other hand, spy shown in Figure 14 is willing to that 2001-349402 specification and the described invention of accompanying drawing are, roughly end face at hydrodynamic bearing member 14, cover 22 is sealed opening, the effective length of hydrodynamic bearing member 14 is elongated, obtain long radial dynamic pressure bearing up and down at interval, so be favourable to the high oil dynamic bearing arrangement of acquisition rigidity.Also have and fully to guarantee hydrodynamic bearing member 14 and advantages above-mentioned base plate 10 bonding lengths.But, because the outer peripheral face of cover 22 becomes faying face with the periphery wall that is formed on the circular all grooves 76 on hydrodynamic bearing member 14 1 end faces, so, exist the problem of ending means reliability deficiency as the envelope of opening at hydrodynamic bearing member 14 and cover can not be coated with between 22 or filling is enough bonding agent.In addition, be formed with big space between interior all side wall surfaces of cover 22 perisporium 221 and above-mentioned all grooves 76, owing to also must filling dynamic pressure generation use lubricating oil, so the more time of the injection of lubricating oil needs, productivity is relatively poor in this space.In addition, the part of volume filling lubricating oil produces bubble easily in lubricating oil, so exist the problem that the generation because of bubble spills lubricating oil easily.

In addition, beyond above-mentioned example, also have a end face with hydrodynamic bearing member 14 to make enclosed construction, just like Figure 15 to structure shown in Figure 17.

The example of Figure 15 is, forms all grooves 88 at an end face of hydrodynamic bearing member 14, and flat cover 86 is embedded in this groove 88 in week, and the periphery of cover 86 and the periphery of above-mentioned all grooves 88 are welded with laser-beam welding machine 90.In this embodiment, the high reliability for the envelope that obtains opening is ended measure must thicken the thickness of cover 86, thickens the problem that exists the interval shortening that makes configuration radial dynamic pressure bearing owing to the thickness that will cover 86.

The example of Figure 16 is, when an end face of hydrodynamic bearing member 14 forms shallow depressed part, form along circumferentially continuously and to all grooves 94 of the groove shape of axial depression at the outer circumferential side of this depressed part, in above-mentioned shallow depressed part, place thin flat cover 92, bonding agent 24 is filled in above-mentioned all grooves 94 bonding and envelope opening only with cover 92 outer peripheral edges portion and hydrodynamic bearing member 14.In this example, will not cover 92 outer peripheral edges portion bending, but engage flat cover 92 by bonding.Therefore, the liquid level of bonding agent 24 is positioned at the position identical with the open end of hydrodynamic bearing member 14, flows into the problem that this bonding agent of rotating shaft patchhole is interfered rotating shaft easily thereby exist bonding agent 24.

The example of Figure 17 is, when an end periphery of hydrodynamic bearing member 14 forms jetty 108 cylindraceous, formation is along the internal perisporium of this jetty 108 and along circumferentially continuously and to all grooves 98 of the groove shape of axial depression, flat cover 92 is embedded interior all sides of above-mentioned jetty 108, bonding agent 24 is filled in above-mentioned all grooves 98, coating adhesive 24 between the internal perisporium of cover 92 face side outer peripheral edges portion and above-mentioned jetty 108 will cover 92 and be fixed on the hydrodynamic bearing member 14 again.Adopt this example, owing to the end depression that makes hydrodynamic bearing member 14 forms jetty 108, thus the part of jetty 108, be used for forming the axial dimension that the radial dynamic pressure bearing uses and be restricted, thus exist the problem of the rigidity reduction of hydrodynamic bearing.

Summary of the invention

The present invention makes in view of above-mentioned problem in the past, its purpose is, the bonding length that can fully obtain rotating shaft and rotating member, the come off thickness that prevents member, the length of capillary seal portion are provided, and can fully guarantee the oil dynamic bearing electric motor of the junction surface length of hydrodynamic bearing member and base plate.

In addition, the present invention also aims to, oil dynamic bearing arrangement and manufacture method thereof are provided, it can increase the axially spaced-apart that forms the radial dynamic pressure bearing and use, can improve the radial dynamic pressure bearing rigidity, and can increase the cover that an end opening of hydrodynamic bearing member is sealed and the bonding area of hydrodynamic bearing member, and can improve bond strength.

The invention of technical scheme 1 is characterised in that to have: hydrodynamic bearing member and make counterrotating rotating shaft with this hydrodynamic bearing member; Be clipped in the lubricating oil between rotating shaft and the hydrodynamic bearing member; Be formed between rotating shaft and the hydrodynamic bearing member, carry out relative the rotation by rotating shaft and rotating member and make the mutual lubricating oil of rotating shaft and hydrodynamic bearing member produce dynamic pressure to rotate the dynamic pressure generating means of supporting rotating shaft freely; Chimeric with the side face of rotating shaft, as to utilize electromagnetism actuating force and the rotating member that is driven in rotation integratedly with rotating shaft; Be formed at the wide diameter portion on the hydrodynamic bearing member; Be located on the rotating member, by preventing that rotating shaft from preventing member from coming off of coming off of hydrodynamic bearing member axially overlapping with the wide diameter portion of hydrodynamic bearing member; And the sealing that axially extends, stops lubricating oil to flow out from the lateral of this axial opposite face of preventing member and wide diameter portion of coming off to the outside, at least with on the relative part of wide diameter portion be formed with axial recess at rotating member, and in this recess, be equipped with wide diameter portion, the junction surface of rotating member and rotating shaft and above-mentioned wide diameter portion overlap at radial direction.

The invention of technical scheme 2 is, in technical scheme 1 described invention, it is characterized in that, on the opposite face of the radial direction of rotating shaft and hydrodynamic bearing member, form the radial dynamic pressure bearing, and on the axial opposite face of the end face of the wide diameter portion side of hydrodynamic bearing member and the rotating member relative, form axial hydrodynamic bearing with it.

The invention of technical scheme 3 is, in technical scheme 2 described inventions, it is characterized in that, on radial dynamic pressure bearing and axial hydrodynamic bearing, be filled with lubricating oil, the outer peripheral face of hydrodynamic bearing member prevents the interval of the inner peripheral surface of member, the conus portion that enlarges gradually to the axial outside with come off relative with it, be located at the axial outside of axial hydrodynamic bearing, utilize this conus portion to constitute the capillary seal portion that prevents usefulness that spills of lubricating oil.

The invention of technical scheme 4 is, in technical scheme 1 described invention, it is characterized in that, rotating member is that disc puts and uses wheel hub, constitutes disc drive appts and uses.

The invention of technical scheme 5 is, in technical scheme 1 described invention, it is characterized in that the outer circumferential side of rotating member has drive magnet, is formed on the inner-rotor type motor of the outer circumferential side configuration motor stator of this drive magnet.

The invention of technical scheme 6 is, in technical scheme 5 described inventions, it is characterized in that, disposes magnetic sheet on the face of the relative base plate of drive magnet, and the magnetic attraction with the axial hydrodynamic force opposite direction that takes place on axial hydrodynamic bearing takes place.

The invention of technical scheme 7 is a kind of oil dynamic bearing arrangements, has: hydrodynamic bearing member and counterrotating rotating shaft with this hydrodynamic bearing member; Be clipped in the lubricating oil in the gap between this rotating shaft and the hydrodynamic bearing member, this gap is so little that can produce the dynamic pressure that is enough to support described rotating shaft in lubricating oil; Accompanying the radially radial dynamic pressure bearing between opposite face that is formed at described rotating shaft and hydrodynamic bearing member on the basis of this lubricating oil; And the cover that has an end face of the above-mentioned hydrodynamic bearing member of rotating shaft patchhole to be sealed to opening, it is characterized in that, have at opening on the end face of hydrodynamic bearing member of rotating shaft patchhole, around peristome, be formed with along the circumferential direction continuously and to all grooves of axial depression, the outer peripheral edges of described cover are formed with to the axial bending and the bending edge portion of extending in described all grooves, in described all grooves, be filled with bonding agent, the bending edge portion of cover is bonding with bonding agent and hydrodynamic bearing member in all grooves, and with covering an end of sealing the hydrodynamic bearing member.

The invention of technical scheme 8 is in technical scheme 7 described inventions, to it is characterized in that the inner peripheral surface of the bending edge portion of cover contacts with all groove inner peripheral surfaces of hydrodynamic bearing member.

The invention of technical scheme 9 is, in technical scheme 7 described inventions, it is characterized in that, the bending edge portion of cover, and all groove inner peripheral surfaces of hydrodynamic bearing member between gapped, this gap is littler than the gap of the outer peripheral face of the bending edge portion of cover and all grooves.

The invention of technical scheme 10 is manufacture methods of a kind of oil dynamic bearing arrangement, has: hydrodynamic bearing member and make counterrotating rotating shaft with this hydrodynamic bearing member; Be clipped in the lubricating oil in the gap between this rotating shaft and the hydrodynamic bearing member, this gap is so little that can produce the dynamic pressure that is enough to support described rotating shaft in lubricating oil; Accompanying the radially radial dynamic pressure bearing between opposite face that is formed at described rotating shaft and hydrodynamic bearing member on the basis of this lubricating oil; And the cover that has an end face of the above-mentioned hydrodynamic bearing member of rotating shaft patchhole to be sealed to opening, the end face that the hydrodynamic bearing member of rotating shaft patchhole is arranged at opening, around peristome, form along the circumferential direction continuously and to all grooves of axial depression, the outer peripheral edges portion of described cover is formed with to the axial bending and the bending edge portion of extending in described all grooves, in described all grooves, be filled with bonding agent, the bending edge portion of cover is bonding with bonding agent and hydrodynamic bearing member in all grooves, one end of bearing is sealed by cover, it is characterized in that, the hydrodynamic bearing member, the end that makes the cover installation side becomes top posture, cover is in from upside to be covered an end face of hydrodynamic bearing member and makes the bending edge portion of this cover enter state in described all grooves, under this state, with the bonding agent filling in all grooves, so that the liquid level of bonding agent is lower than the end face (liquid level of bonding agent becomes the bottom side of all grooves from an end face of hydrodynamic bearing member) of hydrodynamic bearing member of the bending edge portion inboard of cover.

The invention of technical scheme 11 is in technical scheme 10 described inventions, to it is characterized in that under with the state of bonding agent filling in all grooves, placement weight above cover makes adhesive hardens under this state.

Description of drawings

Fig. 1 is the cutaway view of the example of expression oil dynamic bearing electric motor of the present invention.

Fig. 2 is the cutaway view that amplifies the major part of the above-mentioned example of expression.

Fig. 3 is the cutaway view of another example of expression oil dynamic bearing electric motor of the present invention.

Fig. 4 is the cutaway view of the another example of expression oil dynamic bearing electric motor of the present invention.

Fig. 5 is the cutaway view of the another example of expression oil dynamic bearing electric motor of the present invention.

Fig. 6 is the cutaway view of the another example of expression oil dynamic bearing electric motor of the present invention.

Fig. 7 is the cutaway view that amplifies and spin upside down the major part of expression oil dynamic bearing arrangement of the present invention.

Fig. 8 is the cutaway view that amplifies and spin upside down another example of expression oil dynamic bearing arrangement of the present invention.

Fig. 9 is a cutaway view of representing the manufacture method example of oil dynamic bearing arrangement of the present invention by process sequence.

Figure 10 is the cutaway view that amplifies and spin upside down another example of expression oil dynamic bearing arrangement of the present invention.

Figure 11 is the cutaway view of the oil dynamic bearing electric motor example of expression conventional art.

Figure 12 is the cutaway view of another example of oil dynamic bearing electric motor of expression conventional art.

Figure 13 is the cutaway view of oil dynamic bearing arrangement one example of expression conventional art.

Figure 14 is the cutaway view of another example of oil dynamic bearing arrangement of expression conventional art.

Figure 15 is the cutaway view of the another example of oil dynamic bearing arrangement of expression conventional art.

Figure 16 is the cutaway view of the another example of oil dynamic bearing arrangement of expression conventional art.

Figure 17 is the cutaway view of the another example of oil dynamic bearing arrangement of expression conventional art.

Embodiment

Below, with reference to accompanying drawing and according to example oil dynamic bearing electric motor of the present invention, oil dynamic bearing arrangement and manufacture method thereof are described.The oil dynamic bearing electric motor of this example constitutes the disc drive appts that the disc of hard disk etc. is rotated driving, and oil dynamic bearing electric motor of the present invention is also applicable to the Hydrodynamic bearing apparatus of the various device beyond the disc drive appts.The structure division identical with the structure division of Figure 11, Figure 12 example put on identical symbol.

In Fig. 1, Fig. 2, symbol 16 expression rotating shafts, symbol 14 expression hydrodynamic bearing members.Hydrodynamic bearing member 14 is general cylindrical shape shapes, and the embedding of minim gap ground is left in heart hole therein rotating shaft 16.On the outstanding part from the upper end of hydrodynamic bearing member 14 of rotating shaft 16, engage rotating member 20 is arranged by method such as being pressed into.In this embodiment, rotating member 20 is the wheel hubs that put disc and rotation, has flange at the axial pars intermedia of periphery, is provided with disc released part 40 above the flange at this.The junction surface of rotating shaft 16 and rotating member 20 to produce lubricating oil 18 that dynamic pressure uses and does not spill and to the full Zhou Jinhang welding at junction surface from above-mentioned junction surface 36 to the outside in order to make, or utilizes containment member to seal.

Above-mentioned hydrodynamic bearing member 14 has: the cylindrical portion that is used to form radial dynamic pressure bearing 26,26; The axial hydrodynamic bearing 34 that is formed at the outer circumferential side of this cylindrical portion forms the wide diameter portion 28 of usefulness.This wide diameter portion 28, go up in the end (left part among the figure) of above-mentioned cylindrical portion form flange shape, and from an end of above-mentioned cylindrical portion to outstanding formation of axial foreign side (the figure from left end to left).Therefore, the junction surface 36 of rotating member 20 and rotating shaft 16 and above-mentioned wide diameter portion 28 overlap at radial direction.The end face of above-mentioned rotating member 20 is relative with the upper surface of hydrodynamic bearing member 14, and is formed with the recess 38 that holds above-mentioned wide diameter portion 28 with the shape of the upper surface of hydrodynamic bearing member 14 identically.For filling up this recess 38 above-mentioned wide diameter portion 28 is configured in the above-mentioned recess 38, wide diameter portion 28 is covered by above-mentioned recess 38 from upper face side and two sides side, and is formed with the gap that accompanies lubricating oil 18 between the opposite face of hydrodynamic bearing member 14 and rotating member 20.

At the above-mentioned cylindrical portion inner peripheral surface of hydrodynamic bearing member 14, take place on above-mentioned wide diameter portion 28, to be formed with the axial hydrodynamic groove with

groove

74,74 at the radial dynamic pressure that forms near axial two ends as shown in Figure 7.Above-mentioned radial dynamic pressure takes place with

groove

74,74, forms along full week at 2 places up and down of the cylindrical portion inner peripheral surface of hydrodynamic bearing member 14.Groove takes place to use in above-mentioned axial hydrodynamic, also forming in full week above wide diameter portion 28.These dynamic pressures take place to use groove, are rotated by rotating shaft 16 relative hydrodynamic bearing members 14, thereby make rotating shaft 16 and hydrodynamic bearing member 14 mutual lubricating oil 18 that dynamic pressure take place, and constitute and rotate the dynamic pressure generating means of supporting rotating shaft 16 freely.

In the cylindrical portion of above-mentioned hydrodynamic bearing member 14, be inserted with the rotating shaft 16 that is pressed into rotating member 20 one from upside.Be inserted with coming off of ring-type from the periphery downside of hydrodynamic bearing member 14 and prevent member 30, and engage with the inner peripheral surface 54 of rotating member 20.Rotating member 20 has the smooth stage portion 56 continuous with above-mentioned inner peripheral surface 54, and this stage portion 56 also prevents that with above-mentioned coming off member 30 from engaging.In addition, for lubricating oil 18 described later does not spill, end with envelopes such as bonding agents at the junction surface that prevents member 30 and rotating member 20 that comes off.Above-mentioned coming off prevents that member 30 is positioned at the downside of the above-mentioned wide diameter portion 28 of hydrodynamic bearing member 14, and overlaps with the outer peripheral edges portion of wide diameter portion 28 axially leaving minim gap ground.

In the lower end of hydrodynamic bearing member 14, be formed with as described later along all grooves 64 of the circular concentric in full week, in this groove 64, embeds the perisporium of the cover 22 of flat block shape in week, seal the lower ending opening (referring to Fig. 7) of hydrodynamic bearing members 14 with cover 22.The peripheral part of cover 22 ends with envelope such as bonding agent 24 grades in all grooves in the lower end of above-mentioned hydrodynamic bearing member 14.

Between the outer peripheral face of the inner peripheral surface that prevents member 30 and the hydrodynamic bearing member 14 relative that comes off with it, prevent above the member 30 and between below the wide diameter portion 28 of the hydrodynamic bearing member 14 relative coming off with it, between the peripheral wall surfaces of the outer peripheral face of above-mentioned wide diameter portion 28 and the rotating member 20 relative with it, between on the end face of rotating member 20 and the above-mentioned wide diameter portion 28 relative with it, between the outer peripheral face of the inner peripheral surface of hydrodynamic bearing member 14 and rotating shaft 16, and be formed with the gap between the lower surface of above-mentioned cover 22 and rotating shaft 16.These gaps are pressed said sequence mutually and are communicated with, and are filled with lubricating oil 18 in this gap.The gap that comes off between the outer peripheral face of the inner peripheral surface that prevents member 30 and the above-mentioned hydrodynamic bearing member 14 relative with it is open downwards.In addition, the outer peripheral face of the above-mentioned hydrodynamic bearing member 14 that prevents member 30 inner peripheral surfaces relatively comes off, become the conus portion that diminishes under the outer radial, gap between the outer peripheral face of above-mentioned the come off inner peripheral surface that prevents member 30 and hydrodynamic bearing member 14 becomes the capillary seal portion 32 that it enlarges at interval gradually downwards.The liquid level of lubricating oil 18 is arranged in this capillary seal portion 32.

Lubricating oil 18 is injected into the gap from above-mentioned capillary seal portion 32.Form axial hydrodynamic bearing 34 between on the end face of the recess 38 of hydrodynamic bearing member 14 and the above-mentioned wide diameter portion 28 relative, the formation of the two places up and down radial dynamic pressure bearing 26,26 between the outer peripheral face of the inner peripheral surface of hydrodynamic bearing member 14 and rotating shaft 16 with it.In these hydrodynamic bearings, accompany above-mentioned lubricating oil 18.

As shown in Figure 1, the downside of hydrodynamic bearing member 14 is the periphery of half approximately, and interior all sides of the cylindrical portion 12 that forms with central part at base plate 10 are chimeric fixing.The above-mentioned cylindrical portion 12 of base plate 10 enters in rotating member 20 near prevent member 30 to coming off.The outer circumferential side of base plate 10 has perisporium 46, in interior all sides of this perisporium 46, is fixing stator 60.Stator 60 has iron core 48, is wound on a plurality of prominent drive coils of extremely going up 50 that are integrally formed with this iron core 48, and unshakable in one's determination 48 outer peripheral face is fixed on the inner peripheral surface of above-mentioned perisporium 46.Above-mentioned a plurality of prominent utmost point front end is towards the center of motor.

At the outstanding perisporium 44 that is formed with drum in the lower end of rotating member 20, the drive magnet 42 of ring-type is installed at the outer peripheral face of this perisporium 44.Constitute the rotor of motor by this drive magnet 42, rotating member 20, rotating shaft 16.Constitute the prominent utmost point front end face of the iron core 48 of said stator 60, it is relative with the outer peripheral face of above-mentioned drive magnet 42 to leave appropriate gap ground, by the energising of drive coil 50 is switched the rotor rotation is driven.Like this, Fig. 1, example shown in Figure 2 become the oil dynamic bearing electric motor of inner-rotor-type.

As shown in Figure 1, on base plate 10, be fixed with and surround the ring-shaped magnetic plate 52 that above-mentioned cylindrical portion 12 and cross section make the L font.The planar section of magnetic sheet 52 leaves the following relative of appropriate intervals ground and drive magnet 42.Between magnetic sheet 52 and drive magnet 42, produce axial magnetic attraction.This magnetic attraction, the axial dynamic pressure that produces on axial hydrodynamic bearing 34 with respect to the rotation because of rotating member 20 becomes reverse power.Because so the balance of axial power that produces on axial hydrodynamic bearing 34 because of the rotation of rotating member 20 and above-mentioned axial magnetic attraction is the axial position that the energy precision keeps rotating member 20 well.

Above-mentioned lubricating oil 18 injects above-mentioned gap from capillary seal portion 32.This method for implanting is arbitrarily, for example, can inject above-mentioned gap under vacuum state or negative pressure state.In axial hydrodynamic bearing 34 and radial dynamic pressure bearing up and down 26,26, accompany lubricating oil 18.

Come the energising of switching controls by position of rotation to above-mentioned oil dynamic bearing electric motor drive coil 50 according to drive magnet, thereby the magnetic attraction counter-force with the drive magnet 42 of the prominent utmost point of stator core 48 and rotor drives the rotor rotation that comprises drive magnet 42, rotating member 20 and rotating shaft 16.Utilize the rotation of this rotor, make the lubricating oil 18 that is present on the axial hydrodynamic bearing 34 produce axial hydrodynamic power, in addition, make the lubricating oil 18 that is present on the radial dynamic pressure bearing 26,26 produce radial dynamic pressure, rotating shaft 16 still keeps contactless state to rotate relatively with rotating member 20 relative hydrodynamic bearing members 14.

More than Shuo Ming example is, on hydrodynamic bearing member 14, form wide diameter portion 28, on rotating member 20, be provided with by preventing that rotating shaft 16 from preventing member 30 from coming off of coming off of hydrodynamic bearing member 14 axially overlapping with above-mentioned wide diameter portion 28, the lateral of the axial opposite face that prevents member 30 and above-mentioned wide diameter portion 28 from coming off at this axially extends the sealing 32 of prevention lubricating oil 18 to the outside outflow.And, rotating member 20 form axial recess 38 at least with on the relative part of above-mentioned wide diameter portion 28, and in this recess 38, set above-mentioned wide diameter portion 28, the junction surface 36 of rotating member 20 and rotating shaft 16 and above-mentioned wide diameter portion 28 are overlapped at radial direction.Therefore, compare with the thickness at the junction surface 36 of rotating member 20 and rotating shaft 16, can make the thickness of rotating member 20 of the part of the wide diameter portion 28 that holds hydrodynamic bearing member 14 do thin, correspondingly can suppress the short transverse size of motor integral body, can fully guarantee the length at rotating member 20 and the junction surface 36 of rotating shaft 16 again, can guarantee the perpendicularity precision of rotating member 20 and rotating shaft 16.Thus, in the occasion of disc drive, can reduce the runout of disc, and can improve the reliability of cod with motor.

In addition, as mentioned above, owing to can do the thickness of the rotating member 20 that approaches the part of holding hydrodynamic bearing member 14 wide diameter portions 28,, the axial length of capillary seal portion 32 makes enough length so being increased, lubricating oil by guaranteeing q.s and make the high sealing of sealing effectiveness 32, thus the high hydrodynamic bearing of reliability can be obtained.In addition, owing to can enough guarantee the bonding length of hydrodynamic bearing member 14 and base plate 10 longways,, can obtain the oil dynamic bearing electric motor than strong vibration and impact of tolerance from the outside so can obtain enough big bond strength.

Axial hydrodynamic bearing 34 has spiral dynamic pressure groove, and along with the rotation of rotor, lubricating oil is imported into above-mentioned spiral dynamic pressure groove and the dynamic pressure of rising bearing inside, and rotating member 20 is from hydrodynamic bearing member 14 come-ups.At the axial end of hydrodynamic bearing member 14, the lubricating oil 18 that be positioned at the lubricating oil 18 of all sides of axial hydrodynamic bearing 34, promptly is positioned at capillary seal portion 32 spills to the outside easily because of centrifugal force.But as long as by the pump suction that produced by spiral dynamic pressure groove and the amount of the lubricating oil that the amount Billy of mobile lubricating oil moves with centrifugal force is many, lubricating oil just can not spill.In addition, pressurizeed in bearing inside, just can make rotating member 20 effectively from hydrodynamic bearing member 14 come-ups by pump suction with regulation.

Example shown in Figure 3 is to consider such situation, position at the most close external diameter of wide diameter portion 28 forms axial hydrodynamic bearing 34, the interior all side diameters that are made as the spiral dynamic pressure groove of φ d1, axial hydrodynamic bearing 34 when the diameter with capillary seal portion 32 are made as φ d, when the outer circumferential side diameter is made as φ D, become the relation of φ d1＜φ D, promptly, the diameter phi d1 of capillary seal portion 32 is positioned at the formation scope of above-mentioned spiral dynamic pressure groove at radial direction.Therefore, by the pump suction of spiral dynamic pressure groove and the amount that the amount Billy of mobile lubricating oil produces with the centrifugal force of capillary seal portion 32 is many, so lubricating oil can not spill, and can be effectively to the internal pressurization of axial hydrodynamic bearing 34.

Example shown in Figure 4, axial hydrodynamic bearing 34 all lateral deviations in the outer radial of the wide diameter portion 28 of hydrodynamic bearing member 14 are arranged on the external diameter of wide diameter portion 28 and the pars intermedia of internal diameter with moving, make the diameter phi d1 of capillary seal portion 32 and axial hydrodynamic bearing 34 spiral dynamic pressure groove outer circumferential side diameter phi D about equally.In the occasion of this example,, can not spill though the lubricating oil around the wide diameter portion is subjected to centrifugal force.

Example shown in Figure 5 forms axial hydrodynamic bearing 34 in the position of the most close internal diameter of wide diameter portion 28, and makes the relation of φ D＜φ d1.Occasion at this example, compare with the occasion of example shown in Figure 4, because cod becomes interior side direction, so the cod loss torque diminishes, become the low consumption electrification, become and only depend on capillary seal power but act on centrifugal force on the lubricating oil of capillary seal portion 32, the low or cod diameter of rotary speed becomes prerequisite for a short time.

Example shown in Figure 6 is the example that forms axial hydrodynamic bearing 34 between the axial opposite face internal side diameter of wide diameter portion 28, rotating member 20 and hydrodynamic bearing member 14.The occasion of this example about leakage of oil, becomes the condition stricter than example shown in Figure 5, becomes than the example shown in Figure 5 condition of low speed rotation more.In the occasion of Fig. 5, example shown in Figure 6, by setting the effective inflow angle of going into lubricating oil to the spiral dynamic pressure concentrated flow that constitutes axial hydrodynamic bearing 34, even then low speed rotation also can obtain essential dynamic pressure.

Adopting Fig. 5, example shown in Figure 6, as mentioned above, is strict about the leak condition of lubricating oil.But opposite with it, do not produce the rotary speed of oil leak and the condition of cod diameter if adjust, just can reduce the torque loss of cod, have the advantage of the consumption electricity that can extremely reduce the oil dynamic bearing electric motor.Especially, for example Mo Bayier (Japanese: モバイ Le) pretend to this purposes is suitable owing to require low power consumption in the hard disk drive of terminal, in addition, except the effect that reduces torque loss, more increases effect by used motor.

Then, the enclosed construction to an end face of hydrodynamic bearing member 14 describes.One end face of hydrodynamic bearing member 14, the lower surface among the Fig. 1 that more specifically says so, the upper surface among Fig. 7 are fixed with cover 22, utilize an end face opening of cover 22 sealing hydrodynamic bearing members 14.At an above-mentioned end face of hydrodynamic bearing member 14, around the peristome of rotating shaft patchhole, form along the circumferential direction full Zhou Lianxu and to all grooves 64 of the circular concentric of axial depression.Above-mentioned cover 22 is outer peripheral edges portion forms flat cup-shaped member from bending edge portion 221 to axial bending, and the bending edge portion 221 of cover 22 embeds in above-mentioned all grooves 64 of hydrodynamic bearing member 14.The inner peripheral surface of the bending edge portion 221 of cover 22 contacts with the face of interior all sides of above-mentioned all grooves 64 of hydrodynamic bearing member 14.Coating or filling bonding agent 24 in above-mentioned all

grooves

64,22 the bending edge portion 221 of will cover with bonding agent 24 is fixed on the end of hydrodynamic bearing member 14, with covering 22 end faces that seal hydrodynamic bearing members 14.

Promptly, have at opening on the end face of hydrodynamic bearing member 14 of rotating shaft patchhole, be formed with along the circumferential direction with around the peristome continuously and to all grooves 64 of axial depression, outer peripheral edges form above-mentioned bending edge portion 221 from the cover 22 of bending edge portion to axial bending extends in above-mentioned all grooves 221, filling bonding agent 24 in above-mentioned all grooves 64, the bending edge portion 221 of cover 22 is bonding with bonding agent 24 and hydrodynamic bearing member 14 in all grooves 64, with an end of cover 22 sealing hydrodynamic bearing members 14.Therefore, the bonding area of cover 22 and hydrodynamic bearing member 14 can be increased, bond strength can be improved.

In addition, by making said structure, the configuration of radial dynamic pressure bearing 26,26 can be made the roughly total length of the axial length of hydrodynamic bearing member 14, owing to can increase the axial interval of radial dynamic pressure bearing 26,26, can realize slimming, the raising bearing rigidity radially of hydrodynamic bearing member 14.In addition, owing to the bonding length of hydrodynamic bearing member 14 and base plate 10 can be made long enough, so can improve the bond strength of hydrodynamic bearing member 14 and base plate 10.

Cover 22 is carried out bonding bonding agent 24, be maintained in the circular all grooves 64 on the end face that is formed at hydrodynamic bearing member 14, can not flow out to the outside, owing to can not overflow from an end face of hydrodynamic bearing member 14 yet, so can not engage with base plate 10 and produce unfavorable condition, can not hinder the slimming of Hydrodynamic bearing apparatus yet to hydrodynamic bearing member 14.

Because bonding agent 24 liquid levels of bonding cover 22 are lower than the endface position of the hydrodynamic bearing member 14 of quilt cover 22 coverings, and compare the bottom side that is positioned at all grooves 64 with the endface position of hydrodynamic bearing member 14, so bonding agent can not flow into bearing inside, bonding agent can not interfered with rotating shaft 16.

Fig. 1, example shown in Figure 7, although the contacted structure of face of interior all sides of above-mentioned all grooves 64 of the inner peripheral surface of the bending edge portion 221 of clear cover 22 and hydrodynamic bearing member 14, even but example as shown in figure 10 is such, gapped a is also harmless between the face of interior all sides of the inner peripheral surface of cover 22 bending edge portion 221 and above-mentioned all grooves 64.But this gap a will be more less as condition than the gap b that produces between the face of the outer circumferential side of cover 22 bending edge portion 221 and above-mentioned all grooves 64.Its reason is because the bonding agent power of impregnation side little in the gap that capillary force produced becomes bigger cause.Promptly, be owing in the gap a of the inner peripheral surface of the bending edge portion 221 of the little above-mentioned cover 22 in gap and the face of interior all sides of above-mentioned all grooves 64, soak into bonding agent 24, increase the length of the bonding agent 24 that flows into to the junction surface reliably, can improve the cause of bond strength with bigger power of impregnation.

Then, to the manufacture method of Hydrodynamic bearing apparatus of the present invention, especially to as the cover 22 of feature on the structure of the present invention and the assemble method at the junction surface of hydrodynamic bearing member 14, describe with reference to Fig. 9.At first shown in Fig. 9 (a), hydrodynamic bearing member 14 is spun upside down, making the cover installation side is top posture, at an end face of hydrodynamic bearing member 14, i.e. cover 22 on the upper surface in Fig. 9 (a).Cover 22 makes the flat cup-shaped with perisporium 221, along interior all side wall surfaces of all grooves 64 of hydrodynamic bearing member 14 perisporium 221 of cover 22 is entered in all grooves 64.

Then, shown in Fig. 9 (b), with the front end that is coated with pin 68 of bonding agent apparatus for coating towards above-mentioned all grooves 64, while Yi Bian make 14 rotations of hydrodynamic bearing member or move and be coated with pin 68 and bonding agent 24 is fills up in above-mentioned all grooves 64.Thus, cover 22 is sealed on every side.Under this state, shown in Fig. 9 (c), weight 69 is put on cover 22, under this state, make bonding agent 24 sclerosis.

Then, another example shown in Figure 8 is described.The difference of this example and Fig. 1, example shown in Figure 7, be with cover 22 perisporium 221 continuously and the end edge portion of perisporium 221 by forming flange part 222 to the rectangular-shaped bending of foreign side.And this flange part 222 is positioned at described all grooves 64 of hydrodynamic bearing member 14, with the bonding agent 24 of filling in all grooves 64 above-mentioned flange part 222 is adhesively fixed on the hydrodynamic bearing member 14.Adopt this example, the cover 22 and the bond area of hydrodynamic bearing member 14 are increased, fixed cover 22 more firmly.

Illustrated example all is an inner-rotor type, but the present invention also can be applicable to outer-rotor type.

Oil dynamic bearing electric motor of the present invention can not only be used for the disc drive motor, also can be used for the drive motor of various rotary bodies.

Structure of the present invention is, the forming axial recess with the relative part of wide diameter portion at least and set above-mentioned wide diameter portion in this recess of rotating member, rotating member overlaps at radial direction with the junction surface and the above-mentioned wide diameter portion of rotating shaft.Therefore, can make the thickness of rotating member of the part of the wide diameter portion that holds the hydrodynamic bearing member do than the thin thickness at the junction surface of rotation member and rotating shaft, the short transverse size that correspondingly can suppress motor integral body, and fully guarantee the length at the junction surface of rotating member and rotating shaft, can guarantee the vertical precision of rotating member and rotating shaft.

In addition, by rotating member is used wheel hub as disc configuration, with oil dynamic bearing electric motor of the present invention as the disc drive appts motor, thereby the runout of the disc can reduce to rotate the time can improve the rotary speed and the packing density of disc.

In addition, the length of capillary seal portion is increased, lubricants capacity is increased, can obtain long oil dynamic bearing electric motor of life-span.

The bonding length of base plate and hydrodynamic bearing member can be increased, both bond strengths can also be improved.

Adopt the present invention, have at opening on the end face of hydrodynamic bearing member of rotating shaft patchhole, around peristome, be formed with along the circumferential direction continuously and to all grooves of axial depression, outer peripheral edges form above-mentioned bending edge portion from the cover of bending edge portion to axial bending extends in above-mentioned all grooves, bonding agent is filled in this groove in week, the bending edge portion of cover is bonding with bonding agent and hydrodynamic bearing member in all grooves, because a end with cover sealing hydrodynamic bearing member, so can increase the bonding area of cover and hydrodynamic bearing member, can improve bond strength.

In addition,, can dispose the axially spaced-apart of radial dynamic pressure bearing, can make the roughly total length of the axial length of hydrodynamic bearing member, can improve bearing rigidity radially owing to make said structure.

Claims

1, a kind of oil dynamic bearing electric motor is characterized in that having:

The hydrodynamic bearing member reaches and the counterrotating rotating shaft of this hydrodynamic bearing member;

Be clipped in the lubricating oil between described rotating shaft and the hydrodynamic bearing member;

Be formed between described rotating shaft and the hydrodynamic bearing member, make the mutual lubricating oil generation dynamic pressure of rotating shaft and hydrodynamic bearing member and rotate the dynamic pressure generating means of supporting rotating shaft freely by the relative rotation of rotating shaft with rotating member;

Chimeric and utilize the actuating force of electromagnetism and the rotating member that is driven in rotation integratedly with rotating shaft with the side face of rotating shaft;

Be formed at the wide diameter portion on the described hydrodynamic bearing member;

Be located on the described rotating member, by preventing that rotating shaft from preventing member from coming off of coming off of hydrodynamic bearing member axially overlapping with the wide diameter portion of described hydrodynamic bearing member;

The sealing that axially extends from the lateral of the described axial opposite face that prevents member and described wide diameter portion of coming off and stop lubricating oil to flow out to the outside,

Described rotating member be formed with axial recess at least with on the relative part of described wide diameter portion, and in this recess, be equipped with described wide diameter portion,

Described rotating member overlaps at radial direction with the junction surface and the described wide diameter portion of rotating shaft.

2, oil dynamic bearing electric motor as claimed in claim 1, it is characterized in that, on the opposite face of the radial direction of rotating shaft and hydrodynamic bearing member, be formed with the radial dynamic pressure bearing, and on the axial opposite face of the end face of the wide diameter portion side of hydrodynamic bearing member and the rotating member relative, be formed with axial hydrodynamic bearing with it.

3, oil dynamic bearing electric motor as claimed in claim 2, it is characterized in that, on radial dynamic pressure bearing and axial hydrodynamic bearing, be filled with lubricating oil, the outer peripheral face of hydrodynamic bearing member and come off relative with it prevent that conus portion that the interval of the inner peripheral surface of member enlarges gradually to the axial outside is located at the axial outside of described axial hydrodynamic bearing, utilizes this conus portion to constitute and prevents that lubricating oil from spilling the capillary seal portion of usefulness.

4, oil dynamic bearing electric motor as claimed in claim 1 is characterized in that, rotating member is that disc puts and uses wheel hub, constitutes disc drive appts and uses.

5, oil dynamic bearing electric motor as claimed in claim 1 is characterized in that, the outer circumferential side of rotating member has drive magnet, and the stator that forms motor is configured in the inner-rotor type motor of the outer circumferential side of this drive magnet.

6, oil dynamic bearing electric motor as claimed in claim 5 is characterized in that, disposes magnetic sheet on the face of the relative base plate of drive magnet, takes place and the rightabout magnetic attraction of axial dynamic pressure that takes place on axial hydrodynamic bearing.

7, a kind of oil dynamic bearing arrangement has: hydrodynamic bearing member and the relative rotating shaft that is rotated with this hydrodynamic bearing member; Be clipped in the lubricating oil in the gap between this rotating shaft and the hydrodynamic bearing member, described gap is so little that can produce the dynamic pressure that is enough to support described rotating shaft in lubricating oil; Accompanying the radially radial dynamic pressure bearing between opposite face that is formed on described rotating shaft and hydrodynamic bearing member on the basis of this lubricating oil; And to the cover that opening has an end face of the described hydrodynamic bearing member of rotating shaft patchhole to be sealed, it is characterized in that,

Have at opening on the end face of described hydrodynamic bearing member of rotating shaft patchhole, around peristome, be formed with along the circumferential direction continuously and to all grooves of axial depression,

The outer peripheral edges of described cover form the bending edge portion of extending to axial bending in described all grooves,

In described all grooves, be filled with bonding agent, the bending edge portion of described cover in described all grooves with bonding agent and the hydrodynamic bearing member is bonding and the end of sealing the hydrodynamic bearing member with described cover.

8, oil dynamic bearing arrangement as claimed in claim 7 is characterized in that, the inner peripheral surface of the bending edge portion of cover contacts with all groove inner peripheral surfaces of hydrodynamic bearing member.

9, oil dynamic bearing arrangement as claimed in claim 7 is characterized in that, the bending edge portion of cover, and all groove inner peripheral surfaces of hydrodynamic bearing member between gapped, this gap is littler than the gap of the outer peripheral face of the bending edge portion of described cover and described all grooves.

10, a kind of manufacture method of oil dynamic bearing arrangement,

Have: hydrodynamic bearing member and the relative rotating shaft that is rotated with this hydrodynamic bearing member; Be clipped in the lubricating oil in the gap between this rotating shaft and the hydrodynamic bearing member, described gap is so little that can produce the dynamic pressure that is enough to support described rotating shaft in lubricating oil; Accompanying the radially radial dynamic pressure bearing between opposite face that is formed on described rotating shaft and hydrodynamic bearing member on the basis of this lubricating oil; And the cover that has an end face of the described hydrodynamic bearing member of rotating shaft patchhole to be sealed to opening,

Have at opening on the end face of described hydrodynamic bearing member of rotating shaft patchhole, around peristome, form along the circumferential direction continuously and to all grooves of axial depression,

In described all grooves, be filled with bonding agent, the bending edge portion of described cover in described all grooves with bonding agent and described hydrodynamic bearing member is bonding and with the end that described cover is sealed bearing, it is characterized in that,

Described hydrodynamic bearing member, the end that makes described cover installation side becomes top posture, and cover is in from upside covers on the end face of hydrodynamic bearing member and make the bending edge portion of this cover enter state in described all grooves,

Under this state, with the bonding agent filling in described all grooves, so that the liquid level of bonding agent is lower than the end face of hydrodynamic bearing member of inboard of the bending edge portion of cover.

11, the manufacture method of oil dynamic bearing arrangement as claimed in claim 10 is characterized in that, under with the state of bonding agent filling in all grooves weight is put on cover, makes adhesive hardens under this state.